With the BayStars trailing 1-0 in the bottom of the inning, Lopez sent Kris Johnson's 0-2 fastball to the stands behind left field for the go-ahead run at Yokohama Stadium.

With the game-winning blast, the Venezuelan first baseman reached 20 home runs for the sixth straight season.

"I caught hold of it perfectly with my swing," said Lopez, who at 35 is the oldest member of the BayStars roster. "To reach 20 home runs for six years in a row means a lot. I'm quite emotional. I'm so happy to be here playing baseball in Japan."

Haruhiro Hamaguchi (4-3) got the win after fanning six in 6-1/3 innings. He surrendered his only run in the opening frame when he walked Takumi Miyoshi with the bases loaded.

Closer Yasuaki Yamasaki delivered a 1-2-3 ninth for his seventh save of the season and 150th of his career. The 26-year-old is the 15th player in professional baseball history to reach the milestone and the youngest ever.

"I'm very thankful to have the support of my teammates, the coaching staff and so many people around me," Yamasaki said.

Johnson, winner of the 2016 Sawamura Award for Japanese baseball's most outstanding pitcher, dropped to 2-2 after being tagged with the loss. He struck out three while allowing eight hits in his six-inning start.

The second-place BayStars remain a long way behind runaway CL leaders the Yomiuri Giants, but Lopez said catching them is not his team's concern.

"It's important that we don't worry about what the Giants are doing, but just focus on our own games, one at a time," he said.

The Giants saw their buffer over the BayStars cut to 9.5 games following a 5-4 defeat to the Yakult Swallows at Jingu Stadium.

CL leader Hayato Sakamoto hit home runs 26 and 27 of the season in the loss for the Giants.

The Chunichi Dragons beat the Hanshin Tigers 6-4 at Toyohashi Stadium, with Toshiki Abe driving in the go-ahead run on a two-RBI triple in the eighth.